Stomatology, General Hospital of PLA, Beijing, China.
Angle Orthod. 2012 Jan;82(1):48-55. doi: 10.2319/030711-164.1. Epub 2011 Jul 25.
To examine the effect of low-intensity pulsed ultrasound (LIPUS) on orthodontically induced root resorption in rats.
Sixty-four male Wistar rats were divided randomly and equally into four groups (n = 16 rats each). The rats were untreated (negative control) or treated with orthodontic tooth movement without (positive control) or with LIPUS at 100 or 150 MW/cm(2) (LIPUS-treated groups). An initial force of 100 g was applied to the areas between the upper right central incisors and the first molars of the rats for 10 days. Eight rats were randomly chosen from each group, and the root resorption index (RRI) was determined with scanning electron microscopy (SEM). Upper first molar-centered mesial-distal tissue slices were generated from the upper first molars and peridentium of the remaining eight rats from each group. Specimen slices were analyzed with hematoxylin-eosin and tartrate-resistant acid phosphatase staining, osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) immunohistochemistry, and optical microscopy. Analyses of cell number, densitometry, and one-way analysis of variance were performed.
The LIPUS-treated groups displayed decreased RRI values, decreased osteoclast numbers and activity levels, and increased OPG/RANKL expression ratios. High-power SEM revealed reparative cementum in the LIPUS-treated samples.
LIPUS regulates osteoclast differentiation via the OPG/RANKL ratio, evoking a reparative effect on orthodontically induced root resorption in rats.
研究低强度脉冲超声（LIPUS）对大鼠正畸诱导牙根吸收的影响。
将 64 只雄性 Wistar 大鼠随机均分为 4 组（每组 16 只）。大鼠未处理（阴性对照组）或未处理（阳性对照组）或用 100 或 150 MW/cm(2) 的 LIPUS 处理（LIPUS 处理组）进行正畸牙移动。对大鼠右上中切牙和第一磨牙之间的区域施加 100 g 的初始力 10 天。每组随机选择 8 只大鼠，用扫描电子显微镜（SEM）测定牙根吸收指数（RRI）。每组剩余 8 只大鼠的上颌第一磨牙和牙周组织中生成上颌第一磨牙中心近远中组织切片。用苏木精-伊红和抗酒石酸酸性磷酸酶染色、骨保护素（OPG）和核因子 kappa-B 配体受体激活剂（RANKL）免疫组织化学以及光学显微镜对标本切片进行分析。进行细胞计数、密度测定和单因素方差分析。
LIPUS 处理组的 RRI 值降低，破骨细胞数量和活性降低，OPG/RANKL 表达比值增加。高倍 SEM 显示 LIPUS 处理样本中有修复性牙骨质。
LIPUS 通过 OPG/RANKL 比值调节破骨细胞分化，对大鼠正畸诱导的牙根吸收产生修复作用。
